Abstract

A recent discovery has demonstrated that herbivore induced plant volatile compounds from apple trees infested with larvae were highly attractive to con-specific adult male and female leafrollers. However, this work (conducted in New Zealand and Canada) tested only low doses of kairomone. Our US study here was conducted to assess the attractiveness of higher doses of the six apple volatiles putatively identified from apple trees infested by tortricid larvae to the leafroller, Pandemis pyrusana Kearfott. These volatiles included: β-caryophyllene, germacrene D, benzyl alcohol, phenylacetonitrile, (E)-nerolidol, and indole. No volatiles were attractive to P. pyrusana when used alone. However, traps baited with phenylacetonitrile plus acetic acid caught both sexes of P. pyrusana. Traps baited with the other volatiles plus acetic acid caught zero to only incidental numbers of moths (< 1.0). Interestingly, traps baited with phenylacetonitrile plus acetic acid caught significantly more P. pyrusana than traps baited with a commercial sex pheromone lure. The evaporation rate of the acetic acid co-lure was an important factor affecting catches of P. pyrusana with phenylacetonitrile, and studies are needed to optimize the emission rates of both lure components. Further studies are warranted to develop phenylacetonitrile and possibly other aromatic plant volatiles as bisexual lures for the range of tortricid pests attacking horticultural crops.